updated 09/09/2011 AT 8:00 AM ET
•originally published 09/09/2011 AT 10:15 AM ET
Though both of Katherine Schwarzenegger’s parents attended the Fashion’s Night Out event she hosted in Los Angeles Thursday, it was clearly Mother’s Day for the eldest child of estranged spouses Arnold Schwarzenegger and Maria Shriver.
“I have the best mother in the whole entire world,” Katherine, 21, told PEOPLE. “I could not have asked for a better mom. She supports me in everything that I do. She’s always there for me, and we’re, like, inseparable.”
She added: “I always say we talk way too much. I actually tell her everything. I should probably stop doing that! Because we’re just so close.”
Upon arriving at the event – which Katherine hosted at Diane Von Furstenberg to benefit her uncle’s charity, Best Buddies International – Maria Shriver greeted Katherine and her friends with warm embraces, telling her daughter: “You look gorgeous.”
The proud mom later gushed to a friend: “My little girl. … It’s shocking!”